Hospital Bed Parts: Names, Functions and FDA Entrapment Zones

Hospital bed parts are easiest to understand as a system: the frame, the mattress, the side rails, the head and foot boards, the adjustment mechanism and any accessories. FDA describes a “hospital bed system” in exactly those terms, and it maps the gaps between those parts as seven entrapment zones. This guide names the parts, shows which ones differ by bed type, and shows which parts bound each zone. It is written for clinic staff, buyers and students who need to identify a part or understand why a replacement is not “just a part”.

What a hospital bed system includes

FDA’s hospital bed guidance defines a hospital bed system as the bed frame and its components, including the mattress, bed side rails, head and foot board, and any accessories added to the bed. That definition matters because a part rarely works alone: the gap between a rail and a mattress, for example, depends on both.

Parts of a hospital bed

There is no single official parts diagram, so this table works as a text diagram. The part names below follow FDA’s bed system definition and its description of adjustable beds in 21 CFR 880.5100 and 880.5110.

Part	What it is	Source
Bed frame	The structure that carries the other components; part of the bed system.	FDA bed system guidance (2006)
Adjustable sections (head and foot)	Sections that raise and lower to change the contour of the bed. Moving them can change the gap at the rail ends and at the head or foot board.	21 CFR 880.5100, 880.5110; FDA guidance
Mattress	Part of the bed system; its compressibility and position affect rail and board gaps.	FDA bed system guidance
Side rails	Rigid bars attached to the bed, from full length to half, one-quarter and one-eighth length; also called bed side rails, grab bars and safety rails. On AC-powered and hydraulic adjustable beds, the rails are movable and latchable.	FDA guidance; 21 CFR 880.5100
Head board and foot board	The end panels of the bed; part of the bed system.	FDA bed system guidance
Electric motor and remote controls	Built into AC-powered adjustable beds; the controls can be operated by the patient to adjust height and surface contour.	21 CFR 880.5100
Hydraulic mechanism	Used on hydraulic adjustable beds; operated by an attendant to adjust height and surface contour.	21 CFR 880.5110
Accessories	Anything added to the bed; FDA counts these as part of the bed system.	FDA bed system guidance

For the mattress itself, see hospital bed mattress FDA class and support surface groups and hospital bed mattress dimensions. For linen, see hospital bed sheets.

Parts by bed type

FDA classifies adjustable hospital beds by how they are adjusted, and the adjustment mechanism is the main parts difference.

Bed type	Adjustment parts	FDA class	Source
AC-powered adjustable	Built-in electric motor and remote controls operated by the patient; movable and latchable side rails.	Class II (special controls); exempt from premarket notification subject to 21 CFR 880.9	21 CFR 880.5100
Hydraulic adjustable	Hydraulic mechanism operated by an attendant; movable and latchable side rails.	Class I (general controls); exempt from 510(k) subject to 880.9	21 CFR 880.5110
Manual	Product code FNJ “Bed, Manual”.	Class 1	openFDA device classification (regulation 880.5120), checked 2026-10-30
Bariatric	Product code OSI: a bed for patients weighing 500 pounds and above; can expand from 38 to 60 inches in width.	Class 2	openFDA device classification (regulation 880.5100), checked 2026-10-30

Bariatric beds are covered in what is a bariatric bed. For a related equipment parts list, see Hoyer lift parts.

Where the gaps are: the seven entrapment zones

FDA’s guidance (final, March 2006, nonbinding) identifies seven areas where a patient could become trapped between bed parts. The table shows the zone, the parts that bound it and the recommended limit as stated in the guidance text.

Zone	Name in the guidance	Parts involved	Recommended limit
1	Within the Rail	Side rail	Less than 120 mm (4 3/4 in)
2	Under the Rail, Between the Rail Supports or Next to a Single Rail Support	Side rail, rail supports	Less than 120 mm
3	Between the Rail and the Mattress	Side rail, mattress	Less than 120 mm, measured to the mattress compressed by head weight
4	Under the Rail at the Ends of the Rail	Side rail ends, adjustable sections	Less than 60 mm (2 3/8 in) and an opening angle greater than 60 degrees to avoid wedging
5	Between Split Bed Rails	Split side rails	No numeric limit stated; FDA recognizes the area as a potential for entrapment
6	Between the End of the Rail and the Side Edge of the Head or Foot Board	Side rail, head or foot board	No numeric limit stated; FDA recognizes the area as a potential for entrapment
7	Between the Head or Foot Board and the End of the Mattress	Head or foot board, mattress	No numeric limit stated; FDA recognizes the area as a potential for entrapment

FDA gives the rationale for the numbers: head breadth of 120 mm and neck breadth of 60 mm. The guidance notes that the gaps in zones 4 and 6 may change when the head or foot sections of the bed are raised or lowered, and that mattress compressibility, lateral shift and play from loosened rails or boards affect zones 3, 4 and 7. The guidance is aimed at manufacturers, and its recommendations may also help evaluate older beds.

Why a replacement part is not just a part

Because the gaps depend on how the rail, mattress, boards and adjustable sections fit together, swapping one component can change a zone dimension. A different mattress changes zones 3 and 7; a loosened rail or board adds play. FDA treats the gap recommendations as one component of an overall assessment of the whole bed system. A model-specific service manual from the bed’s manufacturer is the reference for the exact parts of a given bed.

Safe use and handling basics

• Keep rails and boards firmly attached; FDA identifies play from loosened rails or boards as a factor in entrapment gaps.
• Use the mattress the bed system was assessed with; FDA lists mattress compressibility among the factors that change gap size.
• Follow the manufacturer’s instructions for use for any adjustment, cleaning or part replacement.

Common mistakes

• Treating the rail, mattress and boards as independent parts rather than as one system.
• Assuming a numeric limit exists for every zone; the guidance states none for zones 5, 6 and 7.
• Assuming hydraulic and AC-powered beds are controlled the same way; one is attendant-operated and the other has patient-operable remote controls.

FAQ

What are the parts of a hospital bed?

FDA defines a hospital bed system as the bed frame and its components, including the mattress, side rails, head and foot board and any accessories. Adjustable beds add a motor with remote controls (AC-powered) or a hydraulic mechanism (hydraulic).

What is the difference between a manual and an electric hospital bed?

An AC-powered adjustable bed has a built-in electric motor and remote controls that the patient can operate (21 CFR 880.5100, Class II). A hydraulic bed is adjusted by an attendant (21 CFR 880.5110, Class I). FDA’s product code FNJ lists “Bed, Manual” as Class 1.

Sources

• 21 CFR 880.5100, AC-powered adjustable hospital bed, law.cornell.edu, checked 2026-10-30.
• 21 CFR 880.5110, Hydraulic adjustable hospital bed, law.cornell.edu, checked 2026-10-30.
• FDA, Hospital Bed System Dimensional and Assessment Guidance to Reduce Entrapment (final, March 2006), fda.gov, checked 2026-10-30.
• openFDA device classification API, regulation numbers 880.5100 to 880.5120, api.fda.gov, queried 2026-10-30.